1. Field of the Invention
The present general inventive concept relates to an audio reproduction system, and more particularly, to a method and an apparatus to reproduce a wide stereo sound by widening a stereo sound output by an audio reproducing apparatus using only speakers of two channels that are disposed close to each other.
2. Description of the Related Art
Since televisions generally include speakers of two channels attached to either the right and the left or the bottom of a main body, a hearing angle is narrow. Hence, a stereo effect generated by DVD/CD reproducers or a television broadcast is reduced, and stereo sounds are heard like mono sounds. In particular, a narrow stereo sound stage reduces the sound quality of a movie and can cause movie viewers to purchase extra speaker systems.
Conventional stereo enhancement systems enhance stereo sounds in front of a listener using only two speakers.
A conventional stereo enhancement system is disclosed in U.S. Pat. No. 6,597,791 (filed on Dec. 15, 1998), entitled “Audio Enhancement System.”
Referring to U.S. Pat. No. 6,597,791, the conventional stereo enhancement system processes a difference signal generated from left and right input signals to create a stereo sound. The difference signal is processed through equalization characterized by amplification of auditory frequencies of high and low bands. The processed difference signal is combined with a sum signal, generated from the left and right input signals, and the original left and right input signals.
However, most conventional stereo enhancement systems have difficulties in designing a crosstalk cancellation filter, so they either use a sum of right and left channels of a stereo sound and a difference between the right and left channels or adjust a phase of and an amplitude of the stereo sound, instead of using a head related transfer function (HRTF). The non-use of HRTFs reduces the amount of calculation required by the conventional stereo enhancement systems, so the conventional stereo enhancement systems can be easily implemented. However, the conventional stereo enhancement systems do not have excellent performances because they are designed without consideration of a head and an auricle of a human being.